4.3 Analysis of the community composition of Insect pollinators
The measured environmental variables (Elevation, humidity, air temperature, and flower resource abundance) are found to have a significant association with the pollinator’s community. Species abundance of pollinators was concentrated in the managed habitat and open trails which were open to the high amount of solar exposer. Activities of the insect pollinators are also highly influenced by such sun exposures (McKinney & Goodell, 2010; Sydenham et al., 2016). Similarly, flower resource abundance was the next positive influencing factor for insect pollinators. The mixture of wildflowers could be a good attraction for all these pollinators as this kind of relation of a different group was also reported in the previous study (Carreck & Williams, 2002).
The complex environmental gradient of high altitude affects the abundance of different taxa of pollinators (Warren et al., 1988). As expected, with the elevation, the abundance of pollinators declined. The reason could be either decreasing of bee and fly attracted flowers or their limited number in higher altitude (Arnold et al., 2009). The plant communities at the high altitude limit the vascular plant and availability of insect pollinators (Mani, 1962). The atmospheric temperature and flower resource abundance have a negative correlation with elevation. Temperature is an important factor for defining the plant composition at higher altitudes (Subedi et al., 2020) and hence alters pollinator abundance. Only a few species of hoverflies that don’t have specific food choices (Kearns, 1992) and big size bees, for instance, Bombus species that can thermoregulate and forage at low temperature were found in the highest altitude of our study area.
RDA
Among Hymenoptera, Apis cerana and A. mellifera were mainly determined by the flower abundance of the Buffer zone whileBombus eximius and B. flavescens were associated with humid forest. The explanation for the Apis spp. could be their preference on floral resources near the nesting area like small size bees (Vulliamy et al., 2006; Gathmann & Tscharntke, 2002) so that they could gather maximum nectar to support the large bee colony (Potts et al., 2003). Large body–sized bees like Bombus spp. could travel away from the nesting area for foraging (Greenleaf et al., 2007) and humid areas to avoid hotter day temperatures (Willmer, 1983).Aglais caschmirensis is the most abundant and frequently seen butterfly in all kinds of habitats (Irungbam et al., 2017). This could be the reason for its presence in the forest as well as managed habitat in our study area. Similarly, the association of Episyrphus balteatus in the human habitat indicates the preference for vegetables such as coriander, buckwheat (Pinheiro et al., 2015) as their host plant. The maximum areas of human habitat were cultivated land.